The present invention relates to a method for improving the control behavior of a controlled automotive vehicle system, in particular an anti-lock brake system (ABS; ESBS: Enhanced Stability Brake System), a driving stability control system (ESP), or another brake system extended by other functionalities, wherein evaluated wheel dynamics data (dyn) and evaluated wheel slip data (slip) are taken into account as a criterion for the initiation of a control intervention for each individual wheel, and the sum thereof is compared to a control threshold (ψ).
In up-to-date ABS brake systems, a control cycle is entered or a control phase change initiated after a control threshold has been exceeded in dependence on the wheel rotational behavior. Predetermined criteria permit defined transitions from one control phase into a subsequent control phase. The control thresholds for entry into an ABS control cycle and the criteria for changing from one control phase into another control phase are based on the wheel slip or the wheel acceleration for each individual wheel, or on a combination of both values (wheel criterion). When a wheel e.g. shows tendencies to run into slip and when, simultaneously, certain predefined deceleration thresholds are exceeded, an ABS control cycle will be initiated. A pressure-maintaining phase or a pressure reduction phase is introduced, depending on the extent of the slip tendency.
A combined control based on acceleration and slip is disclosed e.g. in the handbook ‘Fahrwerktechnik’ (chassis technology), first edition 1993, Wuerzburg, Vogel Verlag (publishing house), page 123 ff. Wheel braking and relative slip are weighted individually for each wheel by way of constant parameters, subtracted from each other, and the so obtained wheel criterion is compared with a control threshold for initiating a control phase or a change of control phase.
An objective is to improve the combined control based on wheel dynamics (acceleration) and slip. It is particularly desired to indicate measures that allow an improved weighting of wheel dynamics and slip.